The present invention relates to a device for reconfigurable power conversion and to a method for operating a device for reconfigurable power conversion, for particular use in parallel computing.
The paradigm of parallel computing is nowadays based on large numbers of networked physical servers which are adapted to commission, execute and decommission virtual servers (or virtual machines) in parallel and independently of each other.
The supply of electrical power within such physical servers is usually based on DC voltage levels of 12V, 5V and the like, while modern silicon devices actually require a plurality of lower device voltages such as 3.3V or 2.5V for peripheral or network connectivity, 1.35V for main memory or 1.0V for main processors, for example. Conversion from supply voltage to the different device voltages is performed by a plurality of DC-DC power converters—one per device voltage—each of which being deployed close to the respective target device, i.e. at the “point of load”. These power converters, which are also called buck converters, include at least a single power stage having a single inductor and a single power transistor, and the output voltage of a power stage may be configured by adapting the duty cycle of a pulse-width modulation (PWM) signal driving the power transistor.
If relatively high currents are required, such as 30 A at 1V, for example, a common measure is to couple several power stages at their power outputs to form so-called multi-phase converters. The term indicates that the several power stages need to be coordinated such that they take turns in providing the desired output voltage. Usually, multi-phase converters are controlled by a programmable converter controller to ensure configurability of output voltage and coordination of power stages, and thus eligible for a wide variety of applications.
In U.S. Pat. No. 6,771,052 B2, a multi-output DC-DC power supply is proposed which has programmable operating characteristics, such as voltage levels, turn-on and off sequences, mono-phase and multi-phase operation, voltage ramp-up and ramp-offs, tracking and protection mode thresholds and action-if-fault strategies. The power supply has a DC-DC converter having an output coupled to a plurality of buck converters. Each buck converter has an output and a control input where the voltage at the output of the buck converter is determined by a duty cycle of at least one pulse width modulated signal provided at the control input of that buck converter. A programmable device has outputs coupled to the control inputs of the buck converters. The programmable device generates the pulse width modulated signals at its outputs for controlling the buck converters to provide voltages corresponding to voltages programmed in the programmable device. The programmable device is programmable and reprogrammable to control the programmable operating characteristics of the power supply.
U.S. Pat. No. 7,844,840 B2 discloses a configurable power control system, which may include a control module and an enable/disable module coupled to a power rail (i.e. an internal power line) to enable and disable power to the power rail. The system can also include a sequencer module coupled to the first and a second power rail to sequence power to the power rail(s). The system can also include a fault detect module to detect system parameters. Additionally, the system can include a memory module to store user input and can store detected faults to be utilized by the control module and other modules to control interrelationships between the enable module, the sequencer module, the fault detect module, power in, and power provided via the power rails.
In U.S. Pat. No. 8,736,102 B1, a multifunctional power converter apparatus and a method are described. The apparatus includes an input power stage configured to receive a DC input voltage from a DC power source and convert the DC input voltage to an AC or DC output voltage. At least one electrical power conversion electronic circuit is connected to an output of the input power stage, a DC output circuit, an AC output circuit, and a controller configured to control the input power stage, the DC output circuit and the AC output circuit. The controller is configured to automatically control the power converter output voltage based on a preselected user input.
With the advent of multi-core processors and multi-processor paradigms, increasing compute power density has become a particular goal in parallel computing. This especially holds for physical server infrastructures based on Systems on a Chip (SoC) which integrate almost all digital devices of a common physical server motherboard, such as in the microserver concept described in R. P. Luijten and A. Doering, The DOME embedded 64 bit microserver demonstrator, in ICICDT, pages 203-206, 2013. It is evident that providing a dedicated set of “point of load” converters per SoC would contradict the goal of increasing compute power density. Moreover, depending on the capacities of market-available power converters, the potential deployment of dedicated power converters in partial utilization is a waste of resources.
Accordingly, it is an aspect of the present invention to improve the power conversion within physical servers.